This study examined the impact of mood on the production of persuasive arguments. Research demonstrates that a happy (as opposed to neutral or sad) mood often leads to less systematic information processing but to greater creativity in production tasks. It was hypothesized that individuals in a happy (as opposed to sad) mood produce more original and more persuasive arguments, especially when asked to advocate an unfamiliar (i.e., counterattitudinal) position. Eighty-seven college students were put in a happy or sad mood and asked to write a proattitudinal or a counterattitudinal essay on one of two topics. Happy subjects generally rated their own essays as being more persuasive than sad subjects did. External ratings revealed, however, that happy subjects' essays were judged to be more persuasive when they were counter-attitudinal but not when proattitudinal. No mood effects on various measures of originality were found. Thus support for the hypothesis was found with respect to judged persuasiveness but not to originality. Results are discussed within the framework of models of mood and cognition.